Computer processing of dates outside the twentieth century

This paper presents practical solutions to problems envisioned in extending computer processing of dates beyond the twentieth century. Many data processing managers are concerned with processing cross-century dates, and in doing so using existing systems, with a minimum of disruption to normal operations. The use of existing date formats can eliminate the need for massive system modifications. Methods of using existing date formats across century boundaries are explained. The use of a format termed the Lilian date format in honor of Luigi Lilio, the inventor of the Gregorian calendar, is introduced. The requirements for an effective date-processing algorithm are presented.